useEffect(() => {
  const list = document.getElementById('list')
  if(props.scrollable) {
    // list has fixed height
    list.addEventListener('scroll', (e) => {
      const el = e.target;
      if(el.scrollTop + el.clientHeight === el.scrollHeight) {
        setLoadMore(true);
      }
    })
  } else {
    // list has auto height
    window.addEventListener('scroll', () => {
      if (window.scrollY + window.innerHeight === list.clientHeight + list.offsetTop) {
        setLoadMore(true);
      }
    })
  }
}, []);